Light emission from suspended graphene: (a) shows the single-layer suspended graphene structure, (b) illustrates the light emission (hot spot) from the center of suspended graphene at room temperature at (< 10−4 Torr). (c,d) The emission radiation peaks from the suspended graphene-based structure under applied electric field, (f) as a function of VDS, where the dotted line presents the calculated energy of the emission peaks related to the interference effect of thermal radiations. (e,f) The integrated intensity referred to the individual emission peak, (e) tri-layer, where Id and VDS correspond to the applied electric power and electric field, respectively, as with the increase of VDS, the applied electric power is decreased, whereas the rapid increase in emission intensity was observed [60].